FILE - In this Sept. 8, 2013, file photo, Green Bay Packers running back Eddie Lacy (27) runs against San Francisco 49ers defensive tackle Ray McDonald (91) during the first half of an NFL football game in San Francisco. Only days after NFL Commissioner Roger Goodell cracked down on domestic violence offenses with far harsher penalties, McDonald might just become the first known case. He faces felony domestic violence charges for an incident during his 30th birthday party with teammates and friends Sunday, Aug. 31, 2014, when police say his alleged victim suffered "visible injuries." (AP Photo/Marcio Jose Sanchez, File)

As expected, Harbaugh's meeting with the media was dominated by questions concerning defensive lineman Ray McDonald, who was arrested on suspicion of felony domestic violence early Sunday.

Harbaugh largely reiterated what he'd stated in a radio interview Tuesday, when he gave his first public comments on the matter: He has zero tolerance for any player who abuses a woman, and he also feels strongly about due process.

Given that, he said he didn't know if McDonald would play when the 49ers open the regular season at Dallas on Sunday. The team, he said repeatedly, was waiting to collect more "information and facts" before making a decision.

On Tuesday, the San Jose Police Department released a brief synopsis report that said the victim, McDonald's fiancee, had "visible injuries."

"This is America," Harbaugh said. "You're innocent until you're proven guilty. I don't know what more I can say about that - the respect for that principle."

That suggests McDonald will play against the Cowboys, unless the 49ers uncover information that was unavailable in the three days following McDonald's arrest. The legal process, of course, doesn't figure to be expedient.

"We all live in America," Harbaugh said. "We all understand that patience is required when it comes to due process. I think we all owe that - we all owe that to everybody that's involved."

Questions involving McDonald occupied the first 10 minutes of Harbaugh's news conference. He spoke in an even, measured tone before becoming exasperated near the end. After Harbaugh invoked the Constitution, a reporter noted the issue was whether McDonald would be allowed to play in a football game, not if he'd go to jail.

Responded Harbaugh: "A man or a woman is not to be punished before due process occurs. I've taken as many questions as I'm going to take on that subject. If you have a question on football."

The 49ers' decision is being closely monitored. Last week, Commissioner Roger Goodell announced new NFL guidelines for employees involved in assault, battery, domestic violence or sexual assault. A first-time offender could receive a six-game suspension with a second offense resulting in a lifetime ban.

On Wednesday, Goodell said the NFL would let the legal process play out before potentially imposing any discipline on McDonald, or any first offender, under the enhanced personal-conduct policy.

"I think the first thing we have to do is let the process play out, get the facts, and make sure you understand all the circumstances," Goodell said to USA Today. "We don't (know the facts) right now, and we're obviously following it very closely. But the policy will be applied uniformly across players, coaches, executives, commissioners. I think we made that very clear in the policy."

McDonald's arrest is the 49ers' 10th since 2012, the most in the NFL over that span. Harbaugh said he is largely to blame for the spate of off-the-field transgressions.

"I take full responsibility - the greatest share of responsibility," he said. "I feel like that is the responsibility of a head coach. (We'll) continue to do our very best. Speaking for myself, speaking for our coaches, and speaking for our organization, that is our job. That is our responsibility. And we'll do our very best. As we have done. But our best needs to be better."

Last year, the 49ers allowed outside linebacker Aldon Smith to play every defensive snap in a loss to the Colts two days after he was arrested for his second DUI. Smith checked himself into a treatment facility and missed the next five games.

A year later, the 49ers appear to be thoroughly vetting McDonald before determining whether he'll play Sunday.

On Wednesday afternoon, McDonald jogged onto the field about 20 minutes late to practice. McDonald walked down from the second floor of the team facility, not the locker room on the ground floor. The coaches' offices and the office of general manager Trent Baalke, among others, are located on the second floor.

On Tuesday, Baalke said he'd spoken with McDonald at length since his arrest and planned to do so in the future.

"We had a lengthy conversation yesterday," Baalke said. "We also had a lengthy conversation today, and we'll continue to have lengthy conversations."